The proposed studies are an extension of past and current NIH supported studies (AI-17346--formerly AI-11921--to applicant since June 15, 1974) which are directed to a thorough understanding of the flight paths of Florida mosquitoes in relation to envrionmental, meteorological, and physiological factors. Emphasis will be placed on those species known to be disease vectors or major pest species. The principal objective is to define the flight paths of mosquitoes, particularly in regard to their visual orientation to visible objects. As the bulk of all mosquito flight is appetential, this study will emphasize the role of vision in the unfed post-teneral female. Individual behavioral responses determine dispersal and, for those species with differing diurnal and nocturnal habitats, the aerial routes between resting and feeding areas. The influence of the major environmental, meterological, and the physiological state of the female on the flights will be evaluated. Non-attractant sampling methods, as suction traps, 'truck' trap, and power aspirators will be used. Suction traps will be used to determine direction of flight in relation to wind direction in both the presence or absence of visual objects. The pattern of flight about visual objects, i.e., whether about or over in relation to dimensions and wind velocity will be studied. The behavior of mosquitoes in the presence of simulated hedges and their readiness to penetrate simulated vegetation will be determined. Using islands, mark, release and recapture experiments will determine whether mosquitoes respond to high silhouettes on the horizon. Diurnal movement between daytime resting sites will also be studied.